Install MGCalendar via CocoaPods
Add MGCalendar

I try work with PMCalendar and MGCalendar.
1) PMCalendar is more abstract, but I can't know how to change it's
position and size. I read it's sources and I think that this component
has difficult architecture and change something is no simple.
2) MGCalendar is simple and easy to use.
Fix bugs in MGCalendar
Add countOfDays between 2 dates method

countOfDays… find how many days between today and selected date in
calendar.
fix bugs
Date distance between selectedDate and today
Merge branch 'WorkWithCalendar'